Pump for refrigerating apparatus



July 1, 1930.. J. H. SIA-IEATS 1,768,638

PUMP FOR REFRIGERATING APPARATUS Filed April 30, 1929 atom-ed daily 1, i

JOHN H. SHEATS, 0F DAYTGN, OHIO, ASSIGNOR TO FRIGIDATRE CORPORATION, OF

DAYTQN, OHIO, A LOBPOB-ATION OF DELAWARE PUMP FOB REFRIGEBATING APPARATUS Application filed April 30,

This invention relates to refrigerating apparatus and especially to the structure of a valve and valve seat in the compressor of said refrigerating apparatus.

An object of the invention is to make the valves more quiet in their seating operation.

Another object of the invention is to effectively seal the valves on the valve seat.

More specifically the invention contemplates providing oil retaining means on the valve seat of a compressor whereby the back slap of the valve is cushioned during the seating operation and Wherebv the valve is efi'ectdively sealed by the oil when the valve is seate Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein. a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a cross section through the body of a compressor disclosingan application of the invention; and

' Fig. 2 is a top view of the valve seats of Fig. 1;

Fig. 3 is an enlarged view'of a portion of a compressor outlet valve and a portion of its seat. 1

Referring to the drawing the compressor 20 is shown preferably provided with two cylinders 21 and .22 which receive two pistons 23 and 24. The head of each piston is preferably provided with an inlet valve and a seat 26 which will he more particularly described later. A. retaining member 34: prevents the valve 25 from raising too far above its seat. The pistons 23 and 24 are preferably reciprocating and mounted upon the crank shaft or a straight shaft provided with eccentrics. On the down stroke of the piston such as is disclosed by the piston 23 a fluid, preferably a refrigerant gas, such as sulphur dioxide asses through this piston valve from the crank case of the compressor into the compression chamber of the cylinder. A certain amount of oil also passes through this valve during the pumping action. The top of the cylinders 21 and 22 carries the valve plate 1929. Serial No. 359,332.

27 which in turn carries a cylinder head 28. The valve plate 27 is provided with ports 29 and 30 and valve seats 31 and 32 for the cylinders 21 and 22 respectively. The valve seats 31 and 32 will be more particularly described later. Plate 27 is provided with recesses 33 surrounding the seats 31 and 32. The valves for the seats include a leaf spring 35 which extends'beyond the valve seats 31 and 32. Buttons 36 and 37 constructed of non-metallic vibration absorbing material such asbakelized paper or the like are interposed between the leaf spring 35 and a second leaf spring 39 and are of such length as to cause the spring 39 to be deflected and tend to hold the spring 35 upon the seats 31 and 32. ,Plate 40 is interposed between springs 35 and 39 and is perforated to receive buttons 36 and 37 and thus provides a guide for said buttons. The leaf springs 35-and 39 and plate 40 are secured at their-middle portions to the valve plate 27 and held in cooperating relation therewith. by one or more screws 41. The spacing washer 42 is placed between the spring 35 and guide plate 40 adjacent the middle of the spring to provide a clearance between the plate and the end of the spring so that the spring function as a flap valve. Plate 40, likewise, serves as a stop for limiting the amount of opening of the valve.

In Fig. 2 is disclosed the preferred construction of the valve seats for the piston inlet valves and the compressor outlet valve. This construction, although disclosed as applied to both sets of valves, may be limited to one of them. The valve seat has the cir= cumferen'ce 46 about the port through which the gas and. oilpass and adjacent thereto is the flat annular surface portion 43. Another fiat annular surface portion is on the exterior of the fiat portion 43 and is separated therefrom by a groove 44. This groove 44. is designed to act as an oil retaining means or at least as a combined oil and gas retaining means.

The refrigerant gas passes from the crank case of the compressor to the cylinder on accountof the lower pressure in the cylinder on the down stroke of the piston. On the up stroke of the piston the gas is forced through the valve plate under pressure of the pliiton. This pressure operation of the as m the crank case suction inlet to the ischar e from the head of the compressor causes t e oil in the crank case to boil and splash through the piston valves to the c linder and then be carried through the ap valve by the piston action. The oil groove 44 retains a part of this oil passing through the valve and from this roove an oil film is generally spread over aie' seat. This groove 44 retains a portion of the oil flowing over the face of the valve seat.

The back slap of the piston valve upon the upward stroke of the piston orthe back slap o the outlet valve on the down stroke of the piston, will be cushioned by strikin this oil mstead of the metallic surface 0 the valve seat. Even if there should arise a condition where the oil is not in suflicient quantity to flood the groove and act directly as a cushioning means, the gas trapped with the oil in the groove will act to cushion the valve on the dashpot principle, This cushioning effect of the valve Wlll lessen considerably the noise of the valve operation. Furthermore when the valve is seated the film of oil between it and the valve seat will effectively seal the valve on its seat. Hence the valve will be more quiet in operation and be more efiectively sealed by use of the invention.

The application of the invention is'not limited to the specific apparatus disclosed. The form and operation of the pistons may obviously be changed. The form of the other elements in t e compressor may also be varied. As previously stated the invention may be applied to either the inlet piston valve or the compressor outlet valve or both. The specific form of the oil retaining means of the valve stroke is also subject to variations. It is preferred, however, to retain the flat surfaces on the valve seat. If desired, the grooves may have rounded edges so that a film of oil will more effectively spread over the flat portions of the valve seat.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a compressor, in combinatiom'a valve seat, a valve cooperating with said seat, means for cushionin the closing of said valve on said seat, sai means including a groove in the seat intermediate and substantially removed from the edges of the seat for receiving oil of the com ressor and tor providing relatively wide at valve seating sur faces.

2. In a compressor, in combination, a valve seat, a flap valve cooperating with said seat,

signature.' v

' JOHN H. SHEATS. 

